Fair value measurements - Schedule of Unrealized Loss on Investments (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Fair value
Less than 12 months	$ 143,642	$ 153,737
12 months or greater	2,480	6,392
Total	146,122	160,129
Unrealized losses
Less than 12 months	(2,140)	(561)
12 months or greater	(20)	(6)
Total	(2,160)	(567)
U.S. government agency securities and treasuries
Fair value
Less than 12 months	113,225	108,695
12 months or greater	2,480	2,496
Total	115,705	111,191
Unrealized losses
Less than 12 months	(2,005)	(505)
12 months or greater	(20)	(4)
Total	(2,025)	(509)
Corporate bonds
Fair value
Less than 12 months	30,417	45,042
12 months or greater	0	3,896
Total	30,417	48,938
Unrealized losses
Less than 12 months	(135)	(56)
12 months or greater	0	(2)
Total	$ (135)	$ (58)